Piston-valve.



Patented Apr. I, I902.

w. HESTDN.

PISTON ,VALVE.

Application filed Apr. 22, 1901.)

(No Model.)

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\VILLIAM IIESTON, OF HOMESTEAD, PENNSYLVANIA.

PISTON VALVE.

' SPECIFICATION forming part of Letters Eatent No. 696,675, dated April 1, 1902.

Application filed April '22, 1901.

To a-ZZ whom, it may concern:

Beit known that LWILLIAM HESTON, a citizen of the United States, residing at Homestead, in the county of Allegheny and State of Pennsylvania,haveinvented a certain new and useful Improvementin Piston-Valves, of which the following is a full, clear, and exact description, reference being had to the accompanying drawings.

The invention relates to pistons, and especially to pistons adapted for use as valves in hydraulic cylinders.

The object of the invention is to provide such a piston with means which will automatically expand the packing-rings as they wear away, with the result of causing them to al ways fit tightly in the cylinder.

The invention consists in the construction and combination of parts hereinafter described, and pointed out definitely in the claims.

In the drawings, Figure l is a central longitudinal sectional view of a double piston embodying my invention. Fig. 2 is a similar View of a single piston embodying my invention.

In the most useful construction the piston is double, as shown in Fig. 1- -that is to say, it has two packed portions lying on the opposite sides of a head a, in which is an annular groove a but the invention may be embodied with a single piston, as shown in Fig. 2. The

piston shown in Fig. 1 has a body A, made of metal and comprising a central head a and two cylindrical stems a a which extend centrally in opposite directions therefrom. For convenience in construction the stem at is made separately and screwed into the head. Embracing each of said stems a a is an expander in the form of a cone B, which is placed with its large end farthest from the head a, which cone is movable, by means to be presently explained, toward said head. Embracing this cone is an internally-tapered split sleeve C, having a cylindrical outer surface, which sleeve is placed with its thick end in contact with the head a, whereby it is restrained from endwise movement when the cone B is being forced toward said head. This so-called split sleeve may, if desired, be split from end to end, and therefore be composed of a plurality of disconnected sections. Embracing this split sleeve are the packing-rings D, which must be expansible' and are preferably made of leather. They are Serial No. 56,977. (No model.)

clamped between the head a and the end of the flange e of a cap E. Within this cap is a coiled spring II, which is compressed between the cap and the large end of the cone B, against which the spring exerts a continuous force to push said cone toward the head a and into the split sleeve 0, with the result of expanding said sleeve 0 and the packingrings D. This action takes place automatically as fast as said packing} rings become worn, wherefore said rings always fit the cylinder.

The construction above described is found at both ends of the piston shown in Fig.1 and is also found in the piston shown in Fig. 2. Some suit-able means must be employed to force and hold the caps E down, so that the packin g-rin gs will be clamped and the springs H be compressed, as stated. The means shown for accomplishing this result consist of nuts a, which are screwed onto the threaded ends of the stems a a Having described my invention, I claim- 1. The combination of a piston comprising a head a, in which .is an external annular groove, and two stems a a cones embracing and movable upon said stems with their small ends pointing toward the head, internally-tapered split sleeves embracing said cones with their thick ends toward and in contact with said head, expansible packingrings embracing said split sleeves, and means for forcing said cones toward said head into said split sleeves, substantially as and for the purpose specified.

2. The combination of a piston comprising a head a, in which is an annular groove, and two stems a a cones embracing and mov able upon said stems with their small ends pointing toward the head, internally-tapered split sleeves embracing said cones with their thick ends toward and in contact with said head, expansible packing-rings embracing said split sle'eves,springs engaging with the large ends of said cones, caps which engage with and compress said springs, and clamp said packing-rings, and means for holding down said caps, substantially as and for the purpose specified.

In testimony whereof I hereunto affix my signature in the presence of two witnesses.

WILLIAM HESTON.

Witnesses:

E. L. THURSTON, FRANK E. BALDWIN.

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